Many database systems can be restored after a crash from a log volume. The restoration of a database from a log volume guards against data loss and ensures data consistency. But restoring a database from a log volume is often compute intensive for the database system and causes the database to be unavailable to users for extended periods of time.
In the drawings, like reference numbers generally indicate identical or similar elements. Additionally, generally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears.